In the recent years, regarding a switch device to be built in an instrument panel of, for example, a vehicle such as an automobile, a switch device having an outer casing 1 formed of a body 2 and an insulator 3 as shown in FIG. 7 has been provided as a related art.
In this case, the body 2 is formed of a rectangular shaped box having a side face portion and a rear face portion which are opened as shown in FIG. 7. Also, the body 2 has an operation button 4 on a front face portion thereof. In an inner section (not shown) of the body 2, a contact holder which is moved by pushing of the operation button 4, a movable contact attached to the contact holder, a restoring spring for applying a restoring force to the contact holder and a holding mechanism such as a so-called heart cam mechanism or the like which holds the contact holder at a position before movement or a position after movement are arranged. In this case, a plurality of engagement holes 5 (two holes in the example shown in FIG. 7) are formed at upper and lower side portions of the body 2, respectively.
On the other hand, the insulator 3 is of a rectangular shaped plate and has a fixed contact (not shown) at a body 2 side and a plurality of connection terminals 6 at a rear side in the innermost area. In this case, engagement pawls 7 of which the number is the same as that of the engagement holes 5, are respectively formed at upper and lower side portions of the insulator 3.
With the above configuration, the insulator 3 is pushed into the side face portion at the right side of the body 2 as shown in FIG. 8 and the engagement pawls 7 are engaged with the engagement holes 5 so as to cause the insulator 3 to be coupled to the body 2, thereby, the outer casing 1 is assembled.
When the operation button 4 is operated to be pushed from the front side in this assembled condition of the insulator 3 and the body 2, the contact holder is moved toward the innermost area against an urging force of the restoring spring so as to bring the movable contact into contact with the fixed contact. At that time, the holding mechanism holds the contact holder at a position after the movement, thereby the operation button 4 is held at a position after the pushing and the movable contact is held at a position where it is in contact with the fixed contact.
Next, when the operation button 4 is operated so as to be pushed again, the holding mechanism releases the holding of the contact holder and the contact holder is moved to a restored condition, thereby the movable contact is restored to a position away from the fixed contact and the operation button 4 is restored to the initial position before the pushing. Meanwhile, the above related switch device is general, but a prior art document representing a switch device shown in FIG. 7 is not found.
In such a related switch device, in the assemble condition of the outer casing 1, a gap for putting the insulator 3 into the body 2 is unavoidably needed at portions between edge parts of upper and lower side portions of the body 2 and upper and lower side portions of the insulator 3. Therefore, when water is poured down onto the outer casing 1 having the above components, the water may enter the inside of the outer casing 1 through the gap so that a trouble such as a short circuit of the fixed contact due to the water may occur.